SU1425736A1 - Device for reading graphic information off crt screen - Google Patents

Abstract

The invention relates to automation, in particular, to devices for controlling the reading of graphic information from an CRT crane, and can be used in human-computer interaction systems. The purpose of the invention is to improve the reliability of the device by providing readout of graphic information of an arbitrary grayscale image, which is ensured by the introduction of the first, 3, 4 and second 5, 6 groups of elements And, the control trigger 12 and memory blocks 7, 8. 1 hp f-ly, 3 yl. with

Description

The invention relates to automation, in particular, to a device for reading graphic information from a screen of a cathode ray tube (CRT) and can be used in interactive computer interaction systems (VIA) of a person with a computer.

The purpose of the invention is to increase the wear of the device.

FIG. I is a block diagram of the device; FIG. 2 is an example. the specific design of the marker formation unit; FIG. 3 shows an example of a specific hon-structured implementation of a memory block.

The device (FIG. 1) includes an amplifier-analyzer 1, a comparator 2, the first group of elements I 3 and 4, the second group of elements I 5 and 6, memory blocks 7 and 8, peBepCHBiibie counters 9 and W, blocks P matches, trigger 12 control 9 block 13 of the formation of the marker, the mixer 14, the video monitor 15, the puller 16 coordinates, made in the form of a light sensor, the block 17 syn-, chronic, made in the whie counter 18 lines 5, generator 19 pulses and counter 20 elements, video source 21

The marker formation unit, (FIG. 2) contains the first 22 and second 23 pulse shapers, differentiator inverters 24 and 25 tert-fr and quarter shapers 26 and 27 pulses, a group of elements OR 28 multiplexers 29 and 30 e of elements I131 and 32,

The memory blocks (fig. 3) soloade the differentiators 33 and 34, the inverter pulse shaper 35, triggers 36 and 37, and the decoder 38,

The device works as follows,

After it is turned on, the signals at the outputs of blocks 7 and 8 d / t, the reversible counters 9 and 10 are in an arbitrary state S, and the source 2 of the video signal begins to produce a zero video signal, personnel and clock sync pulses. The latter arrive on. the input of the clock generator 19 and the counter 19 stro After the excitation of the clock generator 9 by the input horizontal sync pulse, it begins to step up the pulses determining the discretization

screen on the X axis (within the string) and arriving at, the input of the counter 20 elements At the time of coincidence of digital codes, the outputs of a reversible counter 9 for Y and a counter of lines 18, a reversible counter of 10 for X and a counter of 20 elements at the outputs, blocks 11, respectively, generate signals that determine the beginning of the formation of the marker by the corresponding AE.M and incoming to the inputs block 13 of the formation of the marker. The third input of the block 13 receives the meander generated by the trigger 12, which, by connecting to the corresponding output of the video source 25, receives frame sync pulses. Thus, the positive signal level at the input of the block 13 corresponds to the period of the odd field of the standard television through line decomposition.

The signal from the output of block 1 1 for match Y, which is input to the driver 22, determines the beginning of the formation of the marker within the frame (along the Y axis). The shapers 22 and 26 of Y pulses connected via an inverter-differentiator 24, form two pulses of four lines so that the beginning of the first one is determined by the arrival of a signal from the output of the P block of Y, and its trailing edge determines the beginning of the formation of the second Impulse at output. Former 26 „

Thus, at the output of the former 22, the upper half of the marker is determined, and the output pulse of the former 26 defines the lower half. Both of these signals are combined by the element OR 28 ,, the signal at the output of which determines those lines of the television frame. Within which the marker should be formed,

The signal at the output of block 1 of coincidence on X is fed to the input of shaper 23 of pulses on X and determines the beginning of the formation of the marker within the line (along the X axis). Similarly to the procedure of forming the marker along the Y axis, the formers 23 and 27, connected via an inverter-differentiator 25, form two pulses with a duration of eight elements so that the trailing edge of the first of them determines the beginning of the formation of the second, i.e.

314

23 defines the left half of the marker; the output pulse; the former 27, the right. The control inputs of the multiplexers 29 and 30 receive a meander that determines the parity of the interlaced television decomposition floor, and the information inputs of the multiplexers 29 and 30 are connected to the outputs of the shaper 23 and 27 pulses in X in such a way that, with an odd field, the output of the multiplexer 29 produces a signal corresponding to the left half of the marker at the output of the multiplexer

When bringing the light pen to the screen in the area of the marker display, in general, the aperture of the light pen of the puller 16 does not coincide with the center of the marker. The output signal from the light pen of the puller 16 is fed to the input of the amplifier-limiter 1, and through the comparator 2 it is converted into a binary signal suitable for processing by logic blocks. The procedure for determining the direction of movement of the marker is simple, since in the case of a deflection of the aperture

30 - signal of the right half of the marker,. The 15th pen of the puller 16 from the center of the mara with an even field at the output of the multiplexer 29 is the signal of the right half of the marker, and at the output of the multiplexer 30 is the signal of the left half of the marker. The procedure of forming the marker is completed by the operation of logical multiplication of signals determining its position in rows and columns by means of the elements 31 and 32.

In the case of an odd field, the signal at output 5 of the mix signal to the left and at element And 31 determines the right turn if the signal from the output of the computer

A ker in the horizontal direction its aperture corresponds either to the right or left half of the marker, and at the output of the comparator 2 there is a signal only in the period of one of the (even or odd) field of the interlaced scan. If the signal is present within an odd field, then at the output of the element And 5 the output of the marker, at the output of the element 32 and - the left half of the marker. With an even field, the signals at the output of the element And 31 determine the left half of the marker, at the output of the element 32 and 32 - the right half of the marker a. These signals are fed to the input of the mixer 14, the third input of which is connected to the source 21 of the video signal. By means of the mixer 14, the signals at the outputs of the And 31 and 32 elements are mixed into the video signal in such a way that the signal at the output of the And 31 element determines the video signal suppression (blackening of the screen), and the signal at the output of the And 32 element - illuminating the screen. The video signal with the mixed signal of the marker is fed to the input of the video monitor 15. At the same time, along with an arbitrary halftone image determined by the video signal source 21, a rectangular marker consisting of the left and right halves is displayed on the screen of the video monitor 13. Within the limits of the odd half-frame of the left, its half is light, the right is dark, and within the limits of the even half-frame the illumination of the halves is inverse. Such a marker is clearly visible on any background, and its location on the screen is determined by the state of the reversible counters 9 and 10.

rator 2. is present in the period of an even field, then, at the output of the element I, an offset signal is produced

30 in, since the second inputs of the elements And 5 and 6 are connected respectively to the direct and inverse outputs of the trigger 12.

Block 8 implements the storage of control signals for the displacement of the marker up to the end of the nojiHoro frame and the excitation of the forward or inverse inputs of the reverse-counter 10 within the frame sync pulse of an odd field

40 Signals input to the block are recorded in triggers 36 and 37. Differentiator 33 selects the leading edge of the meander field from the output of trigger 12 and starts the generator 35 of an inverse pulse, which forms within 5 television lines within the frame sync pulse. zero potential at the first input of the decoder 38, the remaining inputs

50 of which are received c from the output of the flip-flops 36 and 37. The decoder 38 plays the role of a logical element that implements the operation of the excitation of one of the outputs of block 8 during

55 personnel sync pulses, provided that the second output cannot be excited. More precisely, if there is a signal only on one of the outputs of the trigger 36 or 37, then so.

ker in the horizontal direction its aperture corresponds either to the right or left half of the marker, and at the output of comparator 2 there is a signal only in the period of one of the fields (even or odd) interlaced scan. If the signal is present within an odd field, then at the output of the element I 5 is released

rantor 2. is present in the period of the even field, then the output of the element And 6 produces a shift signal to the right, since the second inputs of the elements 5 and 6 are connected respectively to the direct and inverse outputs of the trigger 12.

Block 8 implements the storage of the marker displacement control signals until the end of the nojiHoro frame and the excitation of the forward or inverse inputs of the reversible counter 10 within the frame sync pulse of the odd field.

Signals input to block 8 are recorded in flip-flops 36 and 37. Differentiator 33 selects the leading edge of the meander field from the output of flip-flop 12 and starts inverse pulse shaper 35, which generates zero potential at the first input for 5 television lines within the frame sync pulse. decoder 38, to the remaining inputs

which receives c gnals from the outputs of the flip-flops 36 and 37. The decoder 38 performs the role of a logic element implementing the operation of exciting one of the outputs of the block 8 during

Adr sync pulse with us-, ovii, that the second output cannot be excited. More precisely, if there is a signal only on one of the outputs of trigger 36 or 37, then so.

The corresponding output of block 8 is excited during a sync pulse. If the state of the flip-flops 36 and 37 is the same (the light pen outside the marker area or its aperture coincides with the center of the marker), the signals at the outputs of block 8 are missing. Differentiator 34 fits the trailing edge of the inverse pulse from the output of shaper 35, by means of which triggers 36 and 37 are reset.

Thus, for example, when mixing the aperture of the light pen of the puller 16 relative to the center of the marker to the left, due to the presence of a signal from the light pen of the puller 16 in only one of the fields, the state of the reversible counter 10 along X decreases by 1 and in the next frame the marker is formed on the i element to the left.

The procedure for controlling a marker within a frame (along the Y axis) is completely similar to that considered. When the aperture of the light pen of the puller 16 is displaced relative to the center of the marker vertically, the signal at the output of the comparator 2 is present only during the formation of one of the halves (upper or lower) of the marker, information about which comes in the signal from the corresponding outputs of the marker forming unit 13. For example, if the aperture of the pen of the puller 16 is shifted upward relative to the marker's Tschentra, then the signal at the output of the element And 3: there is an upward shift, at the output of the element And 4 there is no downward displacement. The state of the outputs of the And 3 and 4 elements is recorded in block 7, the first output of which, within the frame sync pulse, excites the reverse input of the reversing counter 9. Its state decreases by 1 and in the next frame the marker will be formed above.

Claims (2)

Invention Formula 1, A device for reading graphic information from an elec- tron-beam T11-pack screen, containing a ycpi-limiter, the input of which is connected to the output of a coordinate remover optically connected to the screen of the cathode-ray tube, and the output of the amplifier-limiter connected to the input of the comparator, a marker generation unit whose information inputs are connected to the outputs of the corresponding, matching blocks, and formation outputs are information outputs of the device, reversible counters J whose information outputs are connected to one input of the corresponding matching blocks, the other inputs of which are connected to the corresponding information outputs of the synchronization block whose input is the first synchronization input of the device, characterized by the fact that, in order to improve the reliability of the device, the first group of elements I are entered into it, some inputs of which are connected to the output of the comparator, and others are connected to the corresponding outputs of the marker generation unit, the control trigger, the counting input of which is the second clock input devices and my the output is connected to the control input of the marker formation unit, the second group of elements I, some inputs of which are connected to the output of the comparator, and others are connected to the corresponding outputs of the control trigger, and memory blocks whose synchronization inputs are connected to the outputs of the corresponding elements of the first and second groups of control block inputs the memory is connected to the direct output of the control trigger, and the outputs are connected to the summing and subtracting inputs of the corresponding reversible counters. 2. The device according to claim 4, and the fact that the block of the formation of the marker contains the first and second pulse shapers, the inputs of which are the first and second information inputs of the block, and the terminals are connected to the inputs of the corresponding inverter-differentiators the outputs of which are connected to the inputs of the third and fourth pulse generator, respectively, multiplexers, the control inputs of which are the control input of the block, the information inputs are connected to the outputs of the second and fourth pulse shapers, and the outputs are connected to the same inputs of the elements AND GROUPS, the outputs of which are EXISTENT, You use the information outputs of the block, and the element OR, whose inputs connect U257368. yens with the outputs of the first and third tone AND groups, with the outputs of the first pulse shaper, and the outputs of the third pulse shaper are connected to the other inputs of the element are the control outputs of the block. FIG. 2